American fern journal - American Fern Society. (American Fern Society, 1950)

American fern journal - American Fern Society. (American Fern Society, 1951)

American fern journal - American Fern Society. (American Fern Society, 1952)

American fern journal - American Fern Society. (American Fern Society, 1953)

American fern journal - American Fern Society. (American Fern Society, 1954)

American fern journal - American Fern Society. (American Fern Society, 1955)

American fern journal - American Fern Society. (American Fern Society, 1956)

American fern journal - American Fern Society. (American Fern Society, 1957)

American fern journal - American Fern Society. (American Fern Society, 1958)

American fern journal - American Fern Society. (American Fern Society, 1959)

American fern journal - American Fern Society. (American Fern Society, 1960)